How to sell software?

Question

CMS

Good afternoon
There is a finished product, namely a content management system. We have been using it for several years now, together with several partner studios.
Now the question arose how to properly sell from the side of taxes (Is there an IP)? I have to give the buyer a key with which he can download the program from the site and install it.
On the accounting side, is it a product, service, or software license?
What documents need to be presented to the buyer (initial and closing)?
1C Bitrix invoice the offer and close it with a document called a license (in the header licensor, licensee).
To issue a similar document, do you need any software registration? There is a certificate of registration of the computer program.
Thanks

Answer 1

Если выдаёте ключ - значит лицензия на использование. Если делаете кастомизацию, настройку или установку - добавляете ещё и услугу.